Thienylthio-substituted ethers and mineral oil compositions containing the same



United States Patent THIENYLTHIO-SUBSTITUTED ETHERS AND MIN- ERAL OIL COMPOSITIGNS CONTAINING THE SANIE John W. Brooks, Wenonah, N. J., assignor to Socony- Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application August 31, 1950, Serial No. 182,640

13 Claims. (Cl. 252-45) This invention relates to a new class of chemical compounds and to mineral lubricating oil compositions containing the same. More particularly, the invention relates to thienylthio-substituted ethers and to mineral oil compositions containing these compounds as oxidation and corrosion inhibitors.

As is well known, mineral lubricating oils tend to decompose, especially under heat and oxidizing conditions, such as those encountered in use in internal combustion engines. The decomposition products formed in the oil are acidic in nature and exert a corrosive action upon the metal surfaces being lubricated. The present invention is concerned with a novel class of chemical compounds which are highly eflective in counteracting this tendency of an oil to decompose and thus harm the metal surfaces.

In accordance with this invention, it has been found that thienylthio-substituted ethers are excellent addition agents for stabilizing mineral lubricating oilsagainst the deleterious effects of oxidation. It is, therefore, the primary object of this invention to provide lubricating oil compositions containing these new antioxidant compounds. Other and further objects will become apparent as the description of the invention proceeds.

The thienylthio-substituted ethers of the invention are prepared by reacting a thiophenethiol, such as 2-thiophenethiol or 3-thiophenethiol, with a chlorinated ether. The chlorinated ethers contemplated herein are those in which the chlorine atoms are attached to aliphatic carbon atoms rather than to aromatic or heterocyclic carbon atoms, although the ethers contemplated may suitably contain a substituent group of this latter character.

The chlorinated ether may contain one ormore, generally from one to about six, chlorine atoms capable of being substituted by the thienylthio groups to form monoor polythienylthio-substituted products. The chlorine atoms may suitably appear on one or on both of the radicals attached to the ether group, which group in turn may be either an oxygen atom or a sulfur atom.

As non-limiting examples of the chlorinated ethers contemplated herein, there may be mentioned the following:

Alpha,alpha'-dichloroethy1 ether Beta,beta-dichloroethyl ether Gamma,gamma'-dichloropropyl ether Beta,beta-dichloroethyl sulfide Beta,beta'-dichloroisopropyl ether Alpha,alpha,beta,beta-tetrachloroethyl ether Zeta,zeta-dichloro,alpha-phenyl dihexyl ether Theta,theta'-dichloro,alpha-thienyl octyl sulfide Pi-chlorohexadecyl,theta'-cblorooctyl ether Mu,mu'-dichlorododecyl ether Alpha-chloromethyl ether Alpha-phenyl,alpha-chloromethyl ether Alpha,alpha-dichoromethyl phenyl ether Alpha,beta-dichloromethyl ether Delta,delta-dichlorobutyl cyclohexyl ether Alpha-chloromethyl sulfide Epsilon,epsilon-dichloroamyl ether Theta-chlorooctyl dodecyl ether Mu-chlorododecyl sulfide Theta-chlorooctyl hexadecyl ether The reaction between the chlorinated ether and the thiophenethiol is readily carried out by heating the reactants together at moderately elevated temperatures, i. e. from about 50 C. to about 100 C. for a time sufiicient 2,704,275 Patented Mar. 15, 1955 to complete the reaction, i. e. from about 1 to about 10 hours, in the presence of an alkaline material, such as potassium hydroxide.

Generally, the amount of thiophenethiol and chlorinated ether used in the reaction are such that suflicient thiophenethiol is present to replace each of the chlorine atoms present in the chlorinated ether. Thus, for a monochlorinated ether, approximately one mol of thiophenethiol is used per mol of the ether, whereas with a dichlorinated ether two mols of thiophenethiol is generally used. However, particularly with the polyhalogenated ethers, complete substitution of the chlorine atoms of the other is not necessary for the obtainment of products useful as oil additives.

The following equation is typical of the reactions which take place between the chloroethers herein contemplated and thiophenethiol SE A v s-onzon-o-ognt ClOHzGH-O-OzH xon 1 s s Alpha,beta-diehl0roethyl ether whereinX represents a thienylthio radical, R represents an aliphatic hydrocarbon residue, Y represents a radical selected from the group consisting of hydrogen, alkyl, aryl and heterocyclic radicals, W is selected from the group consisting of oxygen and sulfur atoms, Z is selected from the group consisting of alkyl, aryl and heterocyclic radicals, and a and b are integers from 1 to 6, whose total does not exceed 6, c is an integer from 1 to 3; the total number of aliphatic carbon atoms in any one compound not exceeding about 24.

As illustrative examples of the thienylthio ethers contemplated by the invention, there may be mentioned the following:

TYPE (a) Alpha,alpha-dithienylthiomethyl ether Beta,beta-dithienylthioethyl ether Gamma,gamma'-dithienylthiopropyl ether Beta,beta-dithienylthioethyl sulfide Beta,beta-dithienylthioisopropyl ether Alpha,alpha, beta,beta'-tetrathienylthioethyl ether Zeta,zeta'-dithienylthio-alpha-phenylhexyl ether Theta,theta'-dithienylthio-alpha-thienyloctyl sulfide Pi-thienylthiohexadecyl, theta-thienylthiooctyl ether Mu,mu'-dithienylthiododecyl ether TYPE (b) Alpha,thienylthiomethyl ether Alpha,alpha-thienylthiophenylmethyl ether Alpha-thienylthiomethyl sulfide Alpha,alpha-dithienylthiomethyl phenyl ether Alpha,beta-dithienylthioethyl ether Delta,delta-dithienylthiobutyl cyclohexyl ether Epsilon,epsilon-dithienylthioamyl ether Theta,thienylthiooctyl dodecyl ether Mu-thienylthiododecyl sulfide Theta-thienylthiooctyl hexadecyl other To illustrate in further detail the manner in which the products contemplated by this invention are prepared the following example is given.

3 EXAMPLE I Ptepamtia" f pha,beta-didethienylthioethyl ether EXAMPLES 'II..VIII

A number of other thienylthio-substituted ethers were prepared by the same general method employed in the foregoing example for the preparation of alpha,beta-di- 3-tll ailenylthioe thyl ether. These examples are listed in Ta e1.

4 The data in Table II clearly show the efiectivenessof the thienylthioethers in inhibiting oxidation of the oil.

Bubble test This-test determines the effectiveness of an oilin preventing bearing corrosion. In this test, an accurately weighed quarter of a connecting rod bearing having a cadmium-silver alloy surface is placed in a 200 x mm. .testtube,'togetherwith gms. of the'test oil. A 5 mm. glass inlet'tube drawn down'to about l'mm. I. D. for about 30 mm. at one end is placed in the tube. The test tube is placed in a constant temperature bath, maintained at 175? "C. and air blown through the test oil at a rate of 2 liters per hour for 22 hours. The test piece is then removed and weighed. The results are reported in milligrams of bearing weight loss. The results obtaine in this test wit the c mpeu d ei invention are shQwn in 'I'ableIII. The oilused in these TABLE I Material Reacted With B-Thlophenethiol Product Appearance of Product Belem; Percent Gamma, gamma-dichloropropyl ether Beta beta-dichloroisopropyl ether Triglycol dichloride.

Beta-chloroethyl phenyl other A1pha,a1pha -diehloromethyl other.

Beta,beta-dichioro ethyl sulfide- Beta,beta-dlchloroethyl ether ethyl ether VII VIII

Gamma,gamma-di-3-thienylthlopropyl other. ;Beta,beta-di-3-thlenylthioisopropyl' ether.-. 2[2 (3-thienylthlo) ethoxy] 2- (3-thienylthio )di- Beta-fi-thienylthioethyl phenyl ether 'Alpha,alpha-dl-3-thienylthiomethyl ether"...

- Beta,betaedi-3ethienylthioethyl sulfidm.

To demonstrate the effectiveness of the products of this invention as lubricating oil additives, several comparative tests were carried out on mineral lubricating oils alone and on these some oils blended with minor amounts of a number of typical thienylthio-substituted others.

' German tar test ZIhis test is designed to show the tendency of a lubricating oil to oxidize .in use.

In this test, a sample of test .oil (150 grams) is placed in a 2.50 ml. extraction flask equipped with a cork .stopperand-having'a-6 mm. I. D. inlet tube extending through this stopper to the bottomof .the flask. The flask also has a vent tube. The flask is. placed in aconstant temperature .oil bath .and maintained at a temperature of 120 C. throughout the test. Oxygen is passedlthrough the oil via the inlet tube at the-rate of two bubbles per second for 70 hours.

The extent of oxidation'efiectedinthe.oil is reported in terms of the neutralization vnumber(N. N.) thereof, as measured at the completion of :the test. 'Thehigher the N. N. the greater the oxidation which .tooksplace, since the oxidized .productsformedin .Qil ;are-.known to be acidic .in .chara'cter. .The results obtained Withthe blended oil-are competed to .the results obtained with h nblendedoil in each --.ca. .e-

Table .II shows the res Its v b inm wi hthe th enylth o ethers of the inventionrinthis .test. "Theo-ilused was a highly acid-refined coastal distillate having a Saybolt Universal viscosity of 69 seconds at 100 F.

est "wa an AE-ZO sohene fired :P nas ls' n a neutral.

Lauson engine test Several other substituted .e thers .such as gbetmbeta .d' phenylthioethyl ether and betadaeta d deeylthioethyl ether were prepared and testednalong w th.the jsevetal thienylthio-substituted ethers, -a.;Lau'son engine order to compare the de iva ives wi the-3 eny s au stituted ethers inyrespeet-to the oil stabliz gqeharact eristicshi -tes de ermi e .deterietv corrosiveness of "th h use e test-1 amended i a single cylinder, liquid-cooled. uson ,engine haying copper-lead bearings, the engine .helng: operated for 1,QO hours (with inspection periods:e ery= ZQ-hemqs) ,at a speed of 1825 R. P. M.',sthe-oil-rtemperature :beingmaiptrined at approximately 270 andjthejacket.temperature at approximately'2l2" "The results are-reported in terms of milligrams of bearing weight lossrand the-neutralization number (N. N.) of the on and viscosity increase of the oil during the run. "These' fresitlts are compared to the results in a similar on the blank dil. The {re splts obtained in these tests are shown inTableIV. Theoil used in the tests-was an SAE-20:;solvent-.refined: Pennsylvan'ia neutral.

TABLE IV.LAUSON TEST RESULTS 1 Results at the end of 60 hours. Test was stopped at this point because hearing weight loss was very high.

It can be seen from Table IV that the thienylthio ethers inhibit oxidation and corrosion much more effectively than other thio-substituted others.

The thienylthio ethers may be used in lubricating oils in amounts varying from about 0.1 per cent to about per cent by weight, depending upon the particular application for which the oil is designed.

Concentrated solutions of the addition agents in oil are also contemplated herein, such solutions containing upwards of 10 per cent by weight and generally from about 25 to about 75 per cent, such solutions being suitable for marketing, since they provide a readily soluble form of the additives for blending with the oils utilized in preparing the final fortified oil compositions.

Although the thienylthio ethers have been shown herein to be eifective antioxidant agents for addition to lubricating oils, it should be clear that they may also be utilized in other petroleum oil fractions in which antioxidant properties are desired, such as gasoline, fuel oils and heavy lubricants, such as greases, etc.

The compounds of the invention may be used in the lubricating oil, or other hydrocarbon fractions, in conjunction with other additives designed to improve the character of said fractions in different respects, such as pour depressants, viscosity index improvers, detergents, extreme pressure agents, etc.

Although the principles of this invention have been illustrated herein by means of certain specific examples and tests, it is not intended that the scope of the invention be limited thereby, but only as indicated in the following claims.

I claim:

1. A mineral lubricating oil containing a minor proportion, sutficient to stabilize said oil against oxidation, of the compound beta,beta'-di-3-thienylthioethyl ether.

2. A mineral lubricating oil containing a minor proportion, sufiicient to stabilize said oil against oxidation, of the compound alpha,beta-di-3-thienylthioethyl ether.

3. A mineral lubricating oil containing a minor proportion, sufiicient to stabilize said oil against oxidation, of the compound beta,beta'-di-3-thienylthioethyl sulfide.

4. A mineral lubricating oil containing a minor proportion, sufiicient to stabilize said oil against oxidation, of the compound beta,beta'-di-3-thienylthioisopropyl ether.

5. A mineral lubricating oil containing a minor proportion, sufiicient to stabilize said oil against oxidation, of the compound beta-3-thienylthioethyl phenyl ether.

6. The compound beta,beta di 3 thienylthioethyl ether.

7. The compound alpha,beta di 3 thienylthioethyl ether.

6 (18. The compound beta,beta'-di-3-thienylthioethy1 sul- 9: The compound beta,beta' di 3 thienylthioisopropyl ether.

h10. The compound beta 3 thienylthioethyl phenyl et er.

11. A compound of the general formula selected from the group consisting of wherein X represents an unsubstituted thienylthio group, R represents a lower alkyl radical having n hydrogen atoms thereof substituted by X radicals, the X radical in each instance being attached through the thio-sulfur atom thereof to the radical R, W is selected from the group consisting of oxygen and sulphur atoms Z represents a hydrocarbon radical selected from lower alkyl and rhenyl radicals, and n represents an integer from 12. A petroleum oil fraction containing a minor proportion, sufiicient to stabilize said fraction against oxidation, of a compound of the general formula selected from the group consisting of (a) XnR-W-RX and ( b XnR-W-Z wherein X represents an unsubstituted thienylthio group, R represents a lower alkyl radical having it hydrogen atoms thereof substituted by X radicals, the X radical in each instance being attached through the thio-sulfur atom thereof to the radical R, W is selected from the group consisting of oxygen and sulphur atoms Z represents a hydrocarbon radical selected from lower alkyl and phenyl radicals, and n represents an integer from 1 to 2.

13. A mineral lubricating oil containing a minor proportion, sufiicient to stabilize said oil against oxidation, of a compound of the general formula selected from the group consisting of wherein X represents an unsubstituted thienylthio group, R represents a lower alkyl radical having n hydrogen atoms thereof substituted by X radicals, the X radical in each instance being attached through the thio-sulfur atom thereof to the radical R, W is selected from the group consisting of oxygen and sulphur atoms Z represents a hydrocarbon radical selected from lower alkyl and phenyl radicals, and n represents an integer from 1 to 2.

References Cited in the file of this patent UNITED STATES PATENTS 2,479,513 Richter et a1. Aug. 16, 1949 2,497,145 Terry et a1. Feb. 14, 1950 2,528,773 Norris Nov. 7, 1950 2,533,798 Hartough et al. Dec. 12, 1950 2,540,093 Brooks Feb. 6, 1951 2,561,780 Brooks July 24, 1951 2,581,626 Brooks Jan. 8, 1952 

